It is usually considered more pleasurable to hear music, singing or other such complex sounds live, rather than hearing the same sound after it has been converted into an electronic audio signal and re-converted back into audible sound.
Many of the sounds we hear, especially musical notes, are often a composite. For example, a musical note having a basic pitch or fundamental frequency, usually contains components of the fundamental frequency called harmonics. These harmonics create the tonal quality or timbre of the sound, such as a musical note, that is often unique to the musical instrument or other sound producing source. In other words, these harmonics enrich the sound we hear. Numerous sound reproduction systems have been developed in an attempt to add harmonic enhancement to audio signals. However, these systems are often very sophisticated and expensive and the sound quality produced with such systems still falls short of the perceived quality of the original sound heard live.
A relatively unsophisticated and inexpensive system has been developed which produces an enhanced electronic audio signal which, when converted into audible sound, exhibits an improved harmonic quality compared to that of the original input audio signal and has been perceived as more closely duplicating the experience of hearing the original live sound in an acoustically designed environment. This system is disclosed in U.S. Pat. No. 5,361,306, which is assigned to the assignee of the present application. The exemplary circuits disclosed in the 5,361,306 patent include an input stage having a field inducing coil and an output stage having an electromagnetic field receptor (e.g., another coil) and an output. The field inducing coil and the electromagnetic field receptor are weekly coupled to form a magnetic coil audio energy transfer system. Input audio signals are transmitted through the inducing coil to set-up an electromagnetic field. The field inducing coil and the electromagnetic field receptor are weakly coupled such that when an input audio signal is transmitted through the field inducing coil, an enhanced audio signal is available at the output.
The present invention is an improvement to the invention disclosed in the U.S. Pat. No. 5,361,306. The present invention has a less complicated structure and is less expensive.